Settings Router Refactor: Remove route.page legacy property.

chrome/browser/resources/settings/settings_page/settings_router.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * 'settings-router' is a simple router for settings. Its responsibilities:
  *  - Update the URL when the routing state changes.
  *  - Initialize the routing state with the initial URL.
  *  - Process and validate all routing state changes.
  *
  * Example:
  *
  *    <settings-router current-route="{{currentRoute}}">
  *    </settings-router>
  */
 Polymer({
   is: 'settings-router',
 
   properties: {
     /**
      * The current active route. This may only be updated via the global
      * function settings.navigateTo.
      *
-     * currentRoute.page refers to top-level pages such as Basic and Advanced.
-     *
      * currentRoute.section is only non-empty when the user is on a subpage. If
      * the user is on Basic, for instance, this is an empty string.
      *
      * currentRoute.subpage is an Array. The last element is the actual subpage
      * the user is on. The previous elements are the ancestor subpages. This
      * enables support for multiple paths to the same subpage. This is used by
      * both the Back button and the Breadcrumb to determine ancestor subpages.
      * @type {!settings.Route}
      */
     currentRoute: {
       notify: true,
       type: Object,
       value: function() {
-        return this.getRouteFor_(window.location.pathname);
+        return (settings.getRouteForPath(window.location.pathname) ||
+                settings.Route.BASIC);
       },
     },
   },
 
   /**
    * Sets up a history popstate observer.
    * @override
    */
   created: function() {
     window.addEventListener('popstate', function(event) {
       // On pop state, do not push the state onto the window.history again.
-      this.currentRoute = this.getRouteFor_(window.location.pathname);
+      var historicRoute = settings.getRouteForPath(window.location.pathname);
+      assert(historicRoute);

[michaelpg, 2016/07/29 20:28:53]

hmmm is it right to assert rather than return silently? What is the programmer
error the assert catches?

Suppose I make a change that disables a route (or, heck, update Chrome and
restore my pages on restart) and use the back button. That's a valid action for
the user, that should do something smart, right?

[tommycli, 2016/07/29 21:04:40]

Done.

+      this.currentRoute = historicRoute;
     }.bind(this));
 
     settings.navigateTo = this.navigateTo_.bind(this);
   },
 
   /**
-   * Returns the matching canonical route, or the default route if none matches.
-   * @param {string} path
-   * @return {!settings.Route}
-   * @private
-   */
-  getRouteFor_: function(path) {
-    // TODO(tommycli): Use Object.values once Closure compilation supports it.
-    var matchingKey = Object.keys(settings.Route).find(function(key) {
-      return settings.Route[key].path == path;
-    });
-
-    if (!matchingKey)
-      return settings.Route.BASIC;
-
-    return settings.Route[matchingKey];
-  },
-
-  /**
    * Navigates to a canonical route.
    * @param {!settings.Route} route
    * @private
    */
   navigateTo_: function(route) {
     assert(!!route);
 
     if (route == this.currentRoute)
       return;
 
     window.history.pushState(undefined, document.title, route.path);
     this.currentRoute = route;
   },
 });